In the US, HIV prevention targeting Men who have Sex with Men (MSM) appears to be failing, while a syndemic of high alcohol/drug use and unsafe sex is increasing. The Office of AIDS Research at the NIH (FY 2006) has prioritized research that aims to "develop and evaluate methods ... to reduce HIV acquisition .... associated with drug and alcohol use" while CDC has described finding "new approaches to reduce HIV risk among MSM" as of the "highest" priority. In response, our broad long-term objective is to study the impact of structural interventions likely to reduce Alcohol-Related HIV Risk (ARHR) among MSM. Legislation on homosexuality and the growth of gay e-infrastructure are two such structural factors which have become prominent national issues, yet little is known about how either impacts MSM's health and HIV risk behavior. We theorize that gay bars are the environmental structure most driving heavy alcohol use and ARHR, and thus contribute to male-male transmission of HIV, syphilis and gonorrhea. If so, the growing utilization of gay e-environments should lower risk. Similarly, legislation on homosexuality, by mainstreaming or marginalizing MSM, is predicted to have significant health impact on this population. This project has 2 aims: (1) To study, at the community level, how public policy and gay e-infrastructure may be changing the centrality and popularity of gay bars;(2) To study, at the individual level, how public policy and gay e-infrastructure modifies alcohol use and ARHR among Men who use the Internet to seek Sex with Men (MISM). To implement these aims, we have assembled an interdisciplinary team of researchers in HIV prevention, alcohol, law, computer science, demography, Internet research, and homosexuality. This team will conduct a prospective, case-comparison, natural experiment study in 16 cities with different legislation on homosexuality (8=pro, 8=anti) and different levels of gay e-infrastructure (8=strong, 8=weak). How these factors impact risk will be tracked at two levels, annually, over 4 years: (1) the city level, by taking a city-wide census of gay bars/clubs, bar attendance, gay e-infrastructure, and HIV/STI rates;(2) the individual level, by comparing MISM's (n=250 per city;4000 per period) alcohol use and ARHR behavior with men first met (a) in gay bars, (b) online, and (c) in neither environment (with participants acting as their own control). PUBLIC HEALTH RELEVANCE: This study (1) advances methods for online behavioral surveillance;(2) examines how alcohol use impacts HIV risk;and (S)studies how virtual environments and public policy impact a community's structure, alcohol use, and HIV risk behavior. As the first study to examine how legislation and e-infrastructure impacts health of high risk communities, this study will inform key stakeholders and the public, nationally and internationally, on how law and the e-environment impact health and HIV risk.